The aim of the study is to present two early modern oaths preserved in the collections (books of oaths) from the cities of the so called Magdeburg legal district - namely of Wrocław and Świdnica - and their analysis in the context of the development of Jewish oath (juramentum judeorum, sacramentum Hebreorum, Judeneid) in Central Europe. Based on a comparison of the text of the two mentioned oaths with the medieval ones, an attempt will be made to follow the continuity of the given phenomenon and the changes in the mutual relations between the Jewish minority and the Christian majority reflected in the texts of these oaths. The wording of the Jewish oath depends on what purpose it should have served. It was created by Christians, and it was created to be as unbreakable as possible. Considering also the regulations relating to the practical implementation of the oath, we can say the aim was also to show the place and position of the Jewish people within the Christian community. The oath was first and foremost the tool of disciplination and control. For all these reasons, the oath can be a rich source of valuable information on the urban society development and it can offer us a specific insight on its changes during a substantial and long period of its existence.